img = Import["ExampleData/lena.tif"];
data = ImageData[img];
d = data[[All, All, 2]];
{nRow, nCol, nChannel} = Dimensions[data]
d = d*(-1)^Table[i + j, {i, nRow}, {j, nCol}]; (*center, i.e. fftshift like *)
fw = Fourier[d, FourierParameters -> {1, 1}];
(*adjust for better viewing as needed*)
fudgeFactor = 100;
abs = fudgeFactor*Log[1 + Abs@fw];
Labeled[Image[abs/Max[abs], ImageSize -> 300], Style["Magnitude spectrum", 18]]
arg = Arg@fw;
Labeled[Image[arg/Max[arg], ImageSize -> 300], Style["Phase spectrum", 18]]
output
